GB2024203A - Process for preparing disodium iminodiacetate monohydrate - Google Patents
Process for preparing disodium iminodiacetate monohydrate Download PDFInfo
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- GB2024203A GB2024203A GB7915615A GB7915615A GB2024203A GB 2024203 A GB2024203 A GB 2024203A GB 7915615 A GB7915615 A GB 7915615A GB 7915615 A GB7915615 A GB 7915615A GB 2024203 A GB2024203 A GB 2024203A
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- GB
- United Kingdom
- Prior art keywords
- temperature
- disodium iminodiacetate
- monohydrate
- idana2
- iminodiacetate
- Prior art date
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Links
- YSBGCHXLMBAKPV-UHFFFAOYSA-L disodium;2-(carboxylatomethylamino)acetate;hydrate Chemical compound O.[Na+].[Na+].[O-]C(=O)CNCC([O-])=O YSBGCHXLMBAKPV-UHFFFAOYSA-L 0.000 title claims abstract description 29
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 239000002002 slurry Substances 0.000 claims abstract description 49
- HAXVIVNBOQIMTE-UHFFFAOYSA-L disodium;2-(carboxylatomethylamino)acetate Chemical compound [Na+].[Na+].[O-]C(=O)CNCC([O-])=O HAXVIVNBOQIMTE-UHFFFAOYSA-L 0.000 claims abstract description 45
- 239000000243 solution Substances 0.000 claims abstract description 45
- 239000013078 crystal Substances 0.000 claims abstract description 34
- 239000007864 aqueous solution Substances 0.000 claims abstract description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 32
- 239000007787 solid Substances 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 20
- 229920006395 saturated elastomer Polymers 0.000 claims description 17
- 239000012452 mother liquor Substances 0.000 claims description 14
- 238000009835 boiling Methods 0.000 claims description 9
- 238000001816 cooling Methods 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 5
- 230000001376 precipitating effect Effects 0.000 claims description 3
- 150000004682 monohydrates Chemical class 0.000 abstract description 12
- 150000004687 hexahydrates Chemical class 0.000 abstract description 8
- 150000003839 salts Chemical class 0.000 abstract 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 15
- 239000007790 solid phase Substances 0.000 description 14
- BSRDNMMLQYNQQD-UHFFFAOYSA-N iminodiacetonitrile Chemical compound N#CCNCC#N BSRDNMMLQYNQQD-UHFFFAOYSA-N 0.000 description 13
- NBZBKCUXIYYUSX-UHFFFAOYSA-N iminodiacetic acid Chemical compound OC(=O)CNCC(O)=O NBZBKCUXIYYUSX-UHFFFAOYSA-N 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 239000012065 filter cake Substances 0.000 description 5
- 230000003301 hydrolyzing effect Effects 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 239000012047 saturated solution Substances 0.000 description 4
- 239000010949 copper Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910000881 Cu alloy Inorganic materials 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- DFNYGALUNNFWKJ-UHFFFAOYSA-N aminoacetonitrile Chemical compound NCC#N DFNYGALUNNFWKJ-UHFFFAOYSA-N 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 235000012970 cakes Nutrition 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- ZDNLLBKMGXPXSO-UHFFFAOYSA-L disodium 2-(carboxylatomethylamino)acetate hexahydrate Chemical compound O.O.O.O.O.O.N(CC(=O)[O-])CC(=O)[O-].[Na+].[Na+] ZDNLLBKMGXPXSO-UHFFFAOYSA-L 0.000 description 2
- VKYKSIONXSXAKP-UHFFFAOYSA-N hexamethylenetetramine Chemical compound C1N(C2)CN3CN1CN2C3 VKYKSIONXSXAKP-UHFFFAOYSA-N 0.000 description 2
- 150000004677 hydrates Chemical class 0.000 description 2
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical compound N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 159000000000 sodium salts Chemical class 0.000 description 2
- LJAIDEYQVIJERM-UHFFFAOYSA-N 2-[bis(cyanomethyl)amino]acetonitrile Chemical compound N#CCN(CC#N)CC#N LJAIDEYQVIJERM-UHFFFAOYSA-N 0.000 description 1
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 description 1
- 238000003109 Karl Fischer titration Methods 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000008064 anhydrides Chemical class 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000003926 complexometric titration Methods 0.000 description 1
- 238000010908 decantation Methods 0.000 description 1
- 235000021463 dry cake Nutrition 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 235000013905 glycine and its sodium salt Nutrition 0.000 description 1
- 239000004247 glycine and its sodium salt Substances 0.000 description 1
- 239000004312 hexamethylene tetramine Substances 0.000 description 1
- 235000010299 hexamethylene tetramine Nutrition 0.000 description 1
- -1 hydros salt Chemical class 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 239000006193 liquid solution Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000010587 phase diagram Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 229940029258 sodium glycinate Drugs 0.000 description 1
- DZCAZXAJPZCSCU-UHFFFAOYSA-K sodium nitrilotriacetate Chemical compound [Na+].[Na+].[Na+].[O-]C(=O)CN(CC([O-])=O)CC([O-])=O DZCAZXAJPZCSCU-UHFFFAOYSA-K 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- WUWHFEHKUQVYLF-UHFFFAOYSA-M sodium;2-aminoacetate Chemical compound [Na+].NCC([O-])=O WUWHFEHKUQVYLF-UHFFFAOYSA-M 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Disodium iminodiacetate monohydrate is more convenient to store and handle than the hexahyrate salt, and can be recovered from an aqueous solution of disodium- iminodiacetate or from a slurry of crystals of the hexahydrate in such solution by holding the solution at a temperature above about 65 DEG at which the salt crystallizes as the monohydrate or by holding the slurry at a temperature above 65 DEG at which the hexahydrate crystals in equilibrium with the dissolved salt are converted to monohydrate.
Description
SPECIFICATION
Process for preparing disodium iminodiacetate monohydrate
This invention is in the field of disodium iminodiacetate (I DANa2) More particularly, this invention is directed to a new method of preparing the monohydrate of disodium iminodiacetate which has the formula
H-N tCH2COONa)2mH2O.
Two hydrates of IDANa2 are known. These are: (a) disodium iminodiacetate monohydrate, H NkCH2COONa)2: H2O (lDANAa2.H2O), which is taught: (i) on page 115 of Eastman Organic Chemicals Catalog No. 46, 1 971 ; and (ii) in line 32 of column 3 of U.S. Patent No. 3,748,114 (Carlson); and (b) disodium iminodiacetate hexahydrate, H-NkCH2COONa)2.6H2O (IDANa2-6H2O) which is described on page 1176 of
Beilsteins Handbuch Der Organischen Chemie, Vierte Auflage, Drittes Erganzungswerk, Vierter Band, Zweiter Teil, 1963.
In summary; this invention is directed to a new method (or process) for preparing the aforesaid monohydrate, said method comprising:
(a) adjusting the temperature of a starting aqueous solution of disodium iminodiacetate having a first temperature between above about 65"C and the boiling point of said starting aqueous solution, said starting solution preferably being saturated or substantially saturated with IDANa2 at the first temperature, to a second temperature which, as shown by the drawing, is effective for crystallizing solid lDANa2.H2O from said starting solution to form a slurry of solid lDANa2.H2O in a mother liquor consisting essentially of water saturated with lDANa2,the second temperature being above about 65"C;; (b) separating the crystallized solid IDANa2-H2O from the mother liquor at a third temperature which: (i) can be the second temperature; (ii) is above about 65"C; and (iii) as shown by the drawing, will not cause the IDANa2.H2O- crystals to dissolve in the mother liquor; and
(c) recovering the separated solid lDANa2.H2O.
The crystallized solid IDANa2-H2O can be separated from the mother liquor by centrifugation,filtration, or decantation.
An examination of the drawing shows that crystalline IDANa2-H2O can be prepared according to the embodiment of the Summary by:
1. Preparing an aqueous IDANa2 solution having a first temperature between about 80"C and its (said solution's) boiling point, said solution containing at least about 53% IDANa2 (reported as anhydrous
IDANa2), and then cooling said solution to a second temperature effective for crystallizing IDANa2-H2O, the second temperature being above 70"C. The crystallized I DANa2-H2O can be separated at about the second temperature and recovered.
2. Preparing an aqueous IDANa2 solution having a first temperature of about 65-66"C, said solution containing at least about 53% IDANa2 (reported as anhydrous IDANa2) and heating said solution to a second temperature effective for crystallizing I DAN a2- H2O, said second temperature being below about 73"C. The crystallized IDANa2-H2O can be separated at about the second temperature and recovered.
The drawing is a plot showing the solubility of disodium iminodiacetate (reported as anhydrous H-N-H2COONa)2) in water as a function of temperature.
In another embodiment ("Embodiment A") this invention is directed to a process (or method) for preparing lDANa2.H2O, the process comprising:
(a) forming a slurry consisting essentially of solid disodium iminodiacetate in a liquor consisting essentially of water saturated with disodium iminodiacetate, said slurry having a first temperature between about 65"C and its (said slurry's) boiling point;
(b) maintaining the slurry at about said first temperature (or any other temperature between about 65"C and the slurry's boiling point) for a time effective for converting the solid disodium iminodiacetate component of the slurry to solid IDANa2-H2O, said time preferably being about 5-30 minutes;;
(c) separating the solid IDANa2-H2O from the liquor consisting essentially of water saturated with a disodium iminodiacetate while maintaining said slurry at a second temperature (which can be the same as the first temperature) between 65"C and its (said slurry's) boiling point, the second temperature being a temperature effective for maintaining solid phase IDANa2-H2O in the system; and
(d) recovering the separated IDANa2-H2O.
In step (b) of Embodiment A the slurry can be maintained at a temperature higher or lower than the first temperature providing that it (the slurry) is maintained at a temperature of at least about 65"C.
In step (c) of Embodiment A the separation can be conducted at a second temperature which can be the same as, higher, or lower than the first temperature providing that: (i) the second temperature is not below about 65"C; and (ii) the second temperature is not such (see the drawing) that all (or substantially all) of the solid lDANa2.H2O which was present in the slurry at the first temperature dissolved when the slurry is brought to the second temperature.
The upper temperature at which the slurry, consisting essentially of solid disodium iminodiacetate and water saturated with disodium iminodiacetate, is maintained, can be the incipient boiling point thereof, while the lower temperature-must be at least about 65 C (preferably about 70-72"C).
The slurry, consisting essentially of solid disodium iminodiacetate, and a liquor, consisting essentially of water saturated with disodium iminodiacetate, can be prepared by: (a) evaporating water from an aqueous solution of disodium iminodiacetate; (b) reacting sodium hydroxide and iminodiacetonitrile (IDAN) to hydrolyze the IDAN thereby to form disodium iminodiacetate (water can be evaporated if necessary to produce the slurry after hydrolyzing the IDAN); or (c) by adding solid disodium iminodiacetate to water. The solid disodium iminodiacetate can be added as IDANa2-6H2O or as anhydrous disodium iminodiacetate.
Where preparing such slurry by adding solid IDANa2-6H2O to water it may be desirable, because of the high water content of IDANa2-6H2O, to add the solid IDANa2-6H2O to an aqueous IDANa2 solution or even to an aqueous IDANa2 slurry rather than to water per se. If desired, water can be evaporated from the resulting slurry to increase the ratio of solid disodium iminodiacetate to dissolved disodium iminodiacetate in the slurry, thereby increasing the conversion of disodium iminodiacetate to recoverable solid IDANa2-H2O.
Because of our disclosure, still other methods for preparing this slurry will be readily apparent to those skilled in the art.
In another embodiment (Embodiment B) this invention is directed to a process for preparing disodium iminodiacetate monohydrate, said process comprising:
(a) heating a starting aqueous disodium iminodiacetate solution which contains at least 53% of IDANa2 reported as anhydrous IDANa2, said starting solution having a first temperature below about 66"C to a second temperature (e.g., about 68-76"C, see the drawing) effective for precipitating (crystallizing) disodium iminodiacetate monohydrate from the starting solution to form a slurry consisting essentially of a mother liquor consisting essentially of water saturated with disodium iminodiacetate and disodium iminodiacetate monohydrate crystals;;
(b) separating the IDANa2-H2O crystals from the mother liquor at a second temperature effective for maintaining the crystals as a solid phase, said second temperature being at least about 65"C; and
(c) recovering the separated IDANa2-H2O crystals.
The second temperature can be: (a) the same as the first temperature; (b) higher than the first temperature; or (c) lower than the first temperature. In other words it can be any temperature at which solid phase lDANa2.H2O is present in the system. (See the drawing.)
The drawing is, as noted supra, a "solubility curve" comprising a plot showing the solubility of IDANa2 (reported as anhydrous IDANa2) in water as a function of temperature.
In addition to the solubility data reported in the drawing, we have found that the solubility of IDANa2 (reported as percent anhydrous IDANA2) is as set forth in the following table:
Solubility of IDANa2
Temperature, "C Solubility, %
20 25.0
30 29.1
40 35.6
50 38.4
We have found that where IDANa2 is crystallized from water at a temperature below about 65 C the
resulting crystals are disodium iminodiacetate hexahydrate (IDANa2-6H2O), while the crystalline product is
disodium iminodiacetate monohydrate (IDANa2-H2O( where the crystallization is conducted at a temperature
of at least about 65"C. This is indicated on the drawing.
We have also found that where a slurry of IDANa2 in water is maintained at a temperature below about 65"the solid phase (IDANa2) component of the slurry is converted to crystalline IDANa2-6H2O. Of course,
under such temperature, if the IDANa2 component of the slurry is provided as IDANa2-6H2O it remains
unchanged.
The time required for solid phase anhydrous IDANa2 or solid phase IDANa2-H2O to be converted to the hexahydrate will depend on the size of the particles, and, to some extent, on the temperature of the slurry
and on the amount of agitation to which the slurry is submitted. Such time can readily be determined by one skilled in the art who can: (a) take samples of the solid phase from time to time and dry them at room temperature (e.g., 20-30"C, e.g., between sheets of filter paper or blotting paper) to remove surface mother
liquor and occluded mother liquor; and (b) analyze the dried samples for water content (e.g., by the Karl
Fischer method).
We have further found that where a slurry of IDANa2 in water is maintained at or above about 65"C the
solid phase component (IDANa2) is converted to crystalline lDANa2.H2O. This is true whether the IDANa2
component is provided as anhydrous IDANa2 or as IDANa2-6H2O.
The time required for solid phase anhydrous IDANa2 or solid phase lDANa2.6H2O to be converted to the
monohydrate will depend on the size of the particles and, to some extent, on the temperature of the slurry
and the amount (or degree) of agitation to which the slurry is submitted. One skilled in the art can readily
determine such time by using the technique described above.
The drawing also shows that the solubility IDANa2 in water has unexpected aspects in that it (the solubility): (a) increases as temperature increases as to a "maximum" at about 65"C; (b) then declines as temperature increases to a "minimum" at about 70-72 C; and (c) again increases steadily as temperature increases to at least about 1 00 C.
Referring to the drawing, it becomes readily apparent that, because of the surprising shape of the solubility curve:
1. IDANa2-H2O crystals can be prepared by cooling a saturated or nearly saturated solution of IDANa2 in water from a temperature above about 78-80"C to a lower temperature which is above about 70-73"C..
(a) The drawing also shows that IDANa2-H2O crystals can be prepared by cooling such saturated solution or substantially saturated solution below about 70-72"C; however the recovery will be lower and would be substantially zero if, for example: (i) a solution having a temperature below about 84-85"C were cooled to about 65"C; or (ii) or if a solution having a temperature of about 70"C were cooled to about 66"C. (Other similar anomilies will be readily apparent from the drawing.)
2. IDANa2.H2O crystals can be prepared by heating a saturated or nearly saturated solution of IDANa2 having a temperature of about 65"C to about 70-72"C (or even to about 80"C).
Disodium iminodiacetate (IDANa2) is a well known material. As noted supra, two hydrates of this material (IDANa2) are known. These are a hexahydrate (IDANa2-6H2O) and a monohydrate (IDANa2-H2O).
It has been customary to prepare disodium iminodiacetate crystals (an intermediate on the route to iminodiacetic acid) by reacting: (a) ammonia, formaldehyde, and HCN; or (b) hexamethylenetetramine, formaldehyde, and HCN; or (c) glycinonitrile and ammonia in an acidic aqueous medium to form iminodiacetonitrile (IDAN), saponifying (hydrolyzing) the IDAN with aqueous sodium hydroxide to form a hot disodium iminodiacetate solution, and cooling the hot solution to about 25"C to precipitate (crystallize) the disodium iminodiacetate.This procedure produces crystals of lDANa2.6H2O which are difficult to store or handle because: (a) said crystals cake to form large chunks which are difficult to break apart; and (b) said crystals melt when heated to about 40"C, a common summer temperature in storage rooms in tropical, desert, and subtropical areas. The melted crystals, on cooling, form ice-like chunks which are extremely difficult to handle and which are difficult to break up or to dissolve.
IDANa2 solutions and slurries prepared by hydrolyzing IDAN with aqueous sodium hydroxide can contain small amounts of color bodies which are formed while preparing the IDAN. These color bodies will generally remain in solution and thus in the aqueous liquor surrounding the lDANa2.H2O product. Sodium sulfate or sodium chloride (or other sodium salt) depending on the acid used to adjust and maintain the pH of the system in which IDAN was formed can also be present in IDANa2 solutions and slurries prepared by hydrolyzing IDAN. Such IDANa2 solutions and slurries can also contain small amounts of trisodium nitrilotriacetate and sodium glycinate derived from side reactions which occur where forming IDAN.Such side reactions form nitrilotriacetnitrile and glycinonitrile which are hydrolyzed to their respective sodium salts while hydrolyzing IDAN to IDANa2 with aqueous sodium hydroxide solution. Some NaOH may also be present.
Unlike IDANa2-6H2O, disodium iminodiacetate monohydrate (IDANa2-H2O) remains free flowing and neither cakes nor melts nor forms ice-like chunks on storage at temperatures up to at least a bout 60"C, thereby making IDANa2-H2O a useful form for shipping and storing disodium iminodiacetate, especially in areas having a hot climate or in plants having hot storage rooms.
The presence of 6 molecules of water per molecule of the hexahydrate also creates a serious problem where attempting to dry wet filter cake (IDANa2-6H2O) to form anhydrous IDANa2, or lDANa2.H2O, e.g., as a step in the preparation of iminodiacetic acid (IDA), because the filter cake can "melt" (i.e., become liquid) and then dry to form a glass-like chunk which is extremely difficu It to process further.
Unlike a wet filter cake of IDANa2 6H2O, a wet filter cake of IDANa2 H2O can be dried without melting. On the contrary, a wet filter cake of IDANa2-H2O dries to form a dry cake made of particulate disodium iminodiacetate which is easy to handle in a plant and which is convenient for use in the preparation of IDA.
For these reasons, a process which directly yields the monohydrate rather than the hexahydrate of disodium iminodiacetate is highly desirable.
IDA, which can be prepared by acidifying IDANa2, is a well known article of commerce. It is used in metal plating baths. German Patent No. 1,034,946, which is reported in Chem. Abstracts 1960,54, 16237e, describes the use of IDA in cyanide-containing copper (and copper alloy) plating baths. The presence of IDA in such baths causes copper (or the copper alloy) to plate (precipitate) as a bright coating. The use of IDA in the peservation of rubber latex is taught by British Patent No. 800,089, which is reported in Chem. Abstracts 1959,53, 2672i.
The drawing, as noted supra, shows the relationship between temperature and solubility of disodium iminodiacetate, reported as anhydrous disodium iminodiacetate, in water. This chart also shows (see the line extending upward from the point at which the solubility curve intersects 65"C on the chart) that at temperatures below about 65"C the solid phase in equilibrium with a saturated aqueous solution of disodium iminodiacetate is lDANa2-6H2O, while at temperatures above about 65"C the solid phase in equilibrium with such aqueous solution is lDANa2-H2O.
Because of our disclosure, including the drawing, it will be readily apparent to those skilled in the art that, where preparing lDANa2-H2O according to the method of the Summary, the solution fro which IDANa2-H2O is crystallized must contain sufficient IDANa2 to cause IDANa2-H2O to crystallize when the temperature of the solution is adjusted to crystallize IDANa2-H2O. Thus, referring to the drawing, it will be readily apparent that: (a) an aqueous IDANa2 solution saturated with IDANa2 at, for example 73-75"C will yield no solid (crystalline) IDANa2.H2O if cooled to 65-66"C and allowed to stand at 65-66"C until solubility equilibrium is reached; while (b) an aqueous IDANa2 solution saturated with IDANa2 at about 95"C will yield (i) a substantial amount of solid IDANa2-H2O if cooled to about 70-75"C; but (ii) somewhat less solid IDANa2-H2O if said solution is cooled from about 95"C to about 65-66"C and allowed to reach solubility equilibrium.
It will also be readily apparent to those who refer to the drawing that a yield of IDANa2.H2O crystals can be obtained by heating an aqueous IDANa2 solution which is substantially saturated with IDANa2 at 65"C to about 70-75"C and permitting the resulting slurry to reach solubility equilibrium at about 70-75"C.
The process of this invention, while operable at pressures below or above normal atmospheric pressure (760 mm of mercury), is preferably operated at about normal atmospheric pressure.
Our invention will be better understood by referring to the following specific but nonlimiting examples. It is understood that said invention is not limited by these examples which are actually run and which are offered merely as illustrations; it is also understood that modifications can be made without departing from the spirit and scope of the invention.
Example 1
A 140 g portion of lDANa26H2O crystals was weighed into a 300 ml Kjeldahl flask. 10 g of water was added and the mixture was heated to a gentle boil thereby producing a clear solution. The flask was placed in a 70"C water bath and shaken. After about two hours a seed crystal of IDANa2-6H2O was added. Crystallization commenced immediately. The slurry was diluted with about 2 ml of water and then shaken for about 15 hours at 700C and then centrifuged. The recovered crystals were ground to pass a 20 mesh screen and dried at 34"C to constant weight. The product was analyzed for IDANa2 by complexometric titration with Cu(ll) and for water by Karl Fischer titration. The product was found to contain 91.1% IDANa2 and 10.2% H2O.
(Theoretical for IDANa2-H2O is 90.8% IDANa2 and 9.2% H2O.)
Example 2
A 500 g portion of a technical solution containing 30.9% IDANa2 (expressed as the an hydros salt) was boiled to a weight of 297 g. This solution was allowed to cool with stirring to 70"C, and then stirred one hour at 70"C. The crystal slurry was centrifuged. The recovered crystals were dried about 15 hours at 31-32"C. The product weighed 80.7 g and was found by analysis (as in Example 1) to contain 85.4% IDANa2 (reported as anhydrous IDANa2) and 12.6% H2O. The recovery (yield) was 44.6% of theory. A small portion of this product he product analyzing 85.4% IDANa2 and 12.6% H2O) was further dried at 55"C for one day.This material (the small portion which had been dried for one day (ca. 24 hours) at 55"C) was analyzed and found to contain 87.3% IDANa2 (reported as anhydrous IDANa2) and 9.4% H2O.
Example 3
A 100 g portion of the technical 30.9% IDANa2 solution used in Example 2 was heated to 70"C. 166 g of IDANa2-6H2O crystals (61.5% IDANa2) were added at 65-70"C. The resulting slurry was stirred one hour at 70"C and centrifuged. The recovered crystals were dried at 55"C for about 15 hours. The recovered dried crystals weighed 53.4 g. The product was found by analysis to contain 88.8% IDANa2 (reported as anhydrous
IDANa2). This corresponds to a recovery (yield) of 35.7% of theory.
As used herein the term "parts" means parts by weight unless otherwise defined where used and the term "percent" ("%") means parts per hundred.
The solubility curve in which the solubility of IDANa2 in water at different temperatures is plotted against different temperatures, is the boundary in a phase diagram, for the two-phase system, or slurry, of solid crystals in liquid solution - the area above the curve represents solution, and the area below the curve represents crystallized solid in equilibrium with its solution. We have found that the solubility curve has two singularities as shown in the drawing - it exhibits a cusp, at a concentration of about 55% and a temperature of about 65"C., and exhibits a turning point at a concentration of about 52% and a temperature of about 72"'.
(The cusp concentration of about 55% occurs also at a temperature which may be called the "cusp equivalent temperature", - as can be seen from the drawing, this occurs at about 86".) At temperatures below the cusp temperature, the solid phase is the hexahydrate, and at temperatures above the cusp temperature the solid phase is the monohydrate.
Our invention, broadly conceived, is to take advantage of these singularities to produce recoverable IDANa2.H2O by taking an aqueous system containing IDANa2 in a form other than the monohydrate - either as the anhydride or as the hexahydrate - and holding that system at a temperature above the cusp temperature but not above the cusp-equivalent temperature, i.e. at a temperature in the region of the turning point, for a time sufficient to permit the IDANa2 to exist as the monohydrate; the disodium iminodiacetate monohydrate crystals produced in this way can then be separated from the mother liquor (liquid balance of the slurry) and be recovered.
Thus there are four ways of putting this broadly conceived invention into effect
1. One can start from an aqueous solution having a temperature above the cusp temperature (at which any IDANa2 precipitated will be precipitated as the monohydrate) and adjust the temperature so as to effect precipitation of the monohydrate,
2. One can start from an aqueous solution at a temperature below the cusp temperature, and heat the solution to above the cusp temperature, when, providing the concentration is above the turning point concentration, IDANa2.H2O will precipitate,
3. One can start from an aqueous solution at a temperature above the cusp-equivalent temperature and cool the solution to a temperature in the turning point range, when, providing the concentration is above the turning point concentration, lDANa2-H2O will precipitate,
4. One can take a slurry of IDANa2 in its solution and bring it to a temperature at which the crystalline solids in equilibrium with the solution are IDANa2-H2O.
These four ways of putting the invention into effect are claimed in the following claims 1,3,4 and 2 respectively.
Claims (4)
1. A process for preparing disodium iminodiacetate monohydrate, said process comprising:
(a) adjusting the temperature of a starting aqueous solution of disodium iminodiacetate having a first temperature between above about 65"C and the boiling point of said starting aqueous solution to a second temperature which, as shown by the drawing, is effective for crystallizing solid disodium iminodiacetate monohydrate from the starting solution, to form a slurry of solid disodium iminodiacetate monohydrate in a mother liquor consisting essentially of water saturated with disodium iminodiacetate, the second temperature being above about 65"C; (b) separating the crystallized solid disodium iminodiacetate monohydrate from the mother liquor while the temperature of the mother liquor is above about 65"C; and
(c) recovering the separated crystaline disodium iminodiacetate monohydrate.
2. A process for preparing disodium iminodiacetate monohydrate, said process comprising:
(a) forming a slurry consisting essentially of solid disodium iminodiacetate in a liquor consisting essentially of water saturated with disodium iminodiacetate;
(b) bringing the slurry to a temperature between about 65"C and its boiling point, and maintaining the slurry at said temperature for a time effective for converting the solid disodium iminodiacetate to solid disodium iminodiacetate monohydrate and separating the solid disodium iminodiacetate monohydrate from the liquor at a temperature effective for maintaining disodium iminodiacetate monohydrate crystals in the slurry; and
(c) recovering the separated disodium iminodiacetate monohydrate.
3. A process for preparing disodium iminodiacetate monohydrate, said process comprising:
(a) heating a starting aqueous disodium iminodiacetate solution which contains at least 53% disodium iminodiacetate, reported as anhydrous disodium iminodiacetate, said starting solution having a first temperature below about 66"C, to a second temperature which, as shown by the drawing, is effective for precipitating disodium iminodiacetate monohydrate to form a slurry consisting essentially of a mother liquor consisting essentially of water saturated with disodium iminodiacetate and disodium iminodiacetate monohydrate crystals;
(b) separating the disodium iminodiacetate monohydrate crystals from the mother liquor at a temperature effective for maintaining disodium iminodiacetate monohydrate crystals in the slurry, and
(c) recovering the separated disodium iminodiacetate monohydrate crystals.
4. A process for preparing disodium iminodiacetate monohydrate, said process comprising:
(a) cooling a starting solution consisting essentially of disodium iminodiacetate and water, said solution: (i) containing at least about 53% disodium iminodiacetate reported as anhydrous disodium iminodiacetate; and (ii) having a first temperature between about 85"C and its boiling point to a second temperature, the second temperature being a temperature shown by the drawing to be effective for precipitating disodium
iminodiacetate monohydrate crystals; and
(b) separating and recovering the precipitated disodium iminodiacetate monohydrate crystals.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US90315478A | 1978-05-05 | 1978-05-05 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2024203A true GB2024203A (en) | 1980-01-09 |
| GB2024203B GB2024203B (en) | 1982-11-10 |
Family
ID=25417024
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7915615A Expired GB2024203B (en) | 1978-05-05 | 1979-05-04 | Process for preparing disodium iminodiacetate monohydrate |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS54145614A (en) |
| DE (1) | DE2912147A1 (en) |
| FR (1) | FR2424903A1 (en) |
| GB (1) | GB2024203B (en) |
| IT (1) | IT1113445B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0845456A2 (en) * | 1996-11-29 | 1998-06-03 | Basf Aktiengesellschaft | Process for the preparation of a crystalline solid of derivatives of (N,N-diacetic acid) glycine with an adequately reduced hygroscopicity |
-
1979
- 1979-02-27 JP JP2149879A patent/JPS54145614A/en active Pending
- 1979-02-27 IT IT20599/79A patent/IT1113445B/en active
- 1979-03-28 DE DE19792912147 patent/DE2912147A1/en not_active Withdrawn
- 1979-05-04 FR FR7911336A patent/FR2424903A1/en not_active Withdrawn
- 1979-05-04 GB GB7915615A patent/GB2024203B/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0845456A2 (en) * | 1996-11-29 | 1998-06-03 | Basf Aktiengesellschaft | Process for the preparation of a crystalline solid of derivatives of (N,N-diacetic acid) glycine with an adequately reduced hygroscopicity |
| EP0845456A3 (en) * | 1996-11-29 | 1998-06-10 | Basf Aktiengesellschaft | Process for the preparation of a crystalline solid of derivatives of (N,N-diacetic acid) glycine with an adequately reduced hygroscopicity |
| US5981798A (en) * | 1996-11-29 | 1999-11-09 | Basf Aktiengesellschaft | Preparation of a crystalline solid from glycine-N,N-diacetic acid derivatives with sufficiently low hygroscopicity |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2024203B (en) | 1982-11-10 |
| IT1113445B (en) | 1986-01-20 |
| FR2424903A1 (en) | 1979-11-30 |
| JPS54145614A (en) | 1979-11-14 |
| DE2912147A1 (en) | 1979-11-15 |
| IT7920599A0 (en) | 1979-02-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |